Capacity operated automatic flushing system



April 8, 1967 c. E. ATKINS ETAL 39 9 CAPACITY OPERATED AUTOMATICFLUSHING SYSTEM Filed May 22, 1964 ATTORNEYS d1 of the flush valve,

part of the user. This can result in the urinal becoming United StatesPatent 3 314 081 CAPACITY orERATnn AUToMA'rrc FLUSI-IING SYSTEM Carl E.Atkins, Montclair, and Robert L. Ziolkowski, Plainfield, N.J., assignorsto Tiling-Sol Electric Inc., a corporation of Delaware Fiied May 22,1964, Ser. No. 369,543 3 Claims. (Cl. 4-100) In many plumbinginstallations it is desirable, for several diiferent reasons, that flushvalves be operated automatically rather than manually. This isparticularly true in the case of urinals. Where a urinal is manuallyactuated, it has been observed that the urinal flush valve is not alwaysoperated after the urinal is used either because of the reluctance ofthe user to touch the operating hanor because of an oversight on thefoul and offensive and constituting a potential health hazard. In fact,the problem is so acute that many states are now considering makingautomatic flush valves mandatory in public urinals.

In the past, themost successful type of automatic flush valve has beenthat which automatically flushes the urinal at periodic intervals. Theinherent disadvantage of this 'type system is that the flushing of theurinal is not associated with the frequency or time of use of theurinal. This results in wasting water when the urinal is not being usedwith great frequency and results in the mentioned esthetic and healthproblems when the urinal is used extensively. Also, since the automaticsystem flushes the urinal periodically, it is possible that anindividual could be in the process of using the urinal at the moment itis flushed. This may result in wetting the individual or frightening ordisturbing him sufficiently so that he will not be able to complete hisuse ,of the urinal.

To overcome these problems with system which periodically flush theurinal, many automatic-systems which are actuated by actual use of theurinal have been developed. However, each of these systems has inherentdrawbacks and up till now a completely satisfactory user actuatedautomatic flushing system for a urinal has not been devised.

In accordance with the present invention a user actuated automatic flushsystem for a urinal has been devised which overcomes many of the faultsof previous automatic systems. This system employs a capacity sensitivemeans to detect the body capacity of the person using the urinal and hasassociated therewith electric circuit means responsive to the capacitydetected by the capacity sensitive means to operate the flush valve ofthe urinal after the capacity sensitive mean-s detects that a person'has approached the urinal to use it and thereafter has left the area ofthe urinal. Therefore, any urinal in which this system is installed willremain unflushed so long as no one approaches the urinal to use it, andthe urinal will flush only after a person who has used the urinal leavesthe area of use of the urinal. Thus, the flushing of the urinal is tiedto its frequency of use and there is no problem of splashing ordisturbing the user of the urinal since the urinal will not be flusheduntil the party using it leaves the area of the use of the urinal.

To prevent the urinal from being flushed by an occasional passerby theelectric circuit means has been arranged so that a person must remain ina position of use of the urinal for a minimum period of time before thesystem will operate. This eliminates the wasting of water and preventsstartling the occasional passerby.

As in any other system reliability is an important factor in the successof an automatic flushing system, and also in the present system it isimportant that the capacity sensitive means be able to distinguish verysmall variations in capacity since it is necessary that the system workwithout requiring that the user of the urinal touch any fixtures. In thepreferred embodiments of the present invention, a unique oscillator isemployed which is very reliable and in addition enables detection ofcapacities as low as 2 pic0- farads while operating at a frequency inthe range of 2 to 4 kilocycles. .The fact that this oscillator enablesde tection of such small values of capacity while operating at such lowfrequencies means that the syste mdoes not interfere with radiotransmission and reception in the area while making the system verysensitive to small changes of body capacity in the area of the urinal.This oscillator is fully described and claimed in our copendingapplication, Serial No. 388,644, filed August 10, 1964, now v US. Patent3,199,033.

For a better understanding of the present invention and of itsadvantages, both those mentioned above and others which'will be apparenthereafter, reference can be had to the accompanying drawings of which:

FIG. 1 is a schematic representation of an embodiment of the presentinvention as it would be employed with a urinal; and

FIG. 2 is a schematic of a change which can be made in the embodiment ofFIG. 1.

Referring to the embodiment in FIG. I, mounted on the top of a urinal 10is an enclosure 12 which contains within it the flush valve 14 for theurinal, a flush valve operating mechanism 16, such as that disclosed inUS. Patent No. 2,552,625 and a circuit 18 for controlling the flushvalve operating mechanism. The circuit 18 is shown in the drawingoutside the enclosure 12 to simplify the drawing of the embodiment. Oneof the leads 2% for excitation of the flush valve operating mechanism 16is connected to a terminal 22 of the v. 60 cycle line. The other lead 24of the motor is connected to the armature 26 of the relay 28. Thenormally open contact for this armature 26 is connected to the other,grounded, terminal 32. When the relay is en ergized the 115 v. 60 cycleline is therefore connected to the valve operating mechanism 16 causingit to flush the urinal, and when the relay is deenergized the circuitbetween the 115 v.60 cycle line and the mechanism for operating thevalve is open so that the urinal will not be flushed by the valveoperating mechanism 16.

Controlling the energization and the deenergization of the relay 28 is acircuit 34 which controls the current flow through the coil 33 of therelay as a function of the capacity between ground and a metal plate 36positioned on the front of the enclosure 12. This circuit 34 has anoscillator 38 which is coupled by a capacitor 40 to the metal plate 36.The oscillator has variable capacitor 4 2 connected between thecapacitor 40 and the grounded terminal 32, a neon tube 44 and a resistor46 connected in shunt across the variable capacitor, and a fixedcapacitor 48 and resistor 50 connected'in shunt across the neon tube 44.

The capacitors 42 and 48 are charged from a DC. power supply 52 whichconsist-s of a diode 54, a resistor 56 and a capacitor 58 connected inseries across the terminals 22 .and 39 of the 115 v. 60 cycle source. Aresistor 60 connects the point common to capacitors 40, 42 and 48 to thepoint common to capacitor 58 and resistor 56 so that the DC. potentialoutput of the power supply is applied across the variable capacitor 42and current flows through resistor 60 from the D.C. power supplycharging capacitors 42 and 48 with respect to ground. When eithercapacitor 42 or 48 exceeds the breakdown potential of the neon tube 44,the neon tube 44 breaks down and both capacitors 42 and 48 dischargethrough it. Discharge current for capacitor 42 travels from one side ofthe capacitor through the neon tube 44 and resistor 46 to the other sideof the capacitor while the discharge current for capacitor 48 travelsfrom the one side of the capacitor .48 through the neon tube 44 andresistor 50. When the voltage on the capacitors 42 and 48 drops due todischarging through the neon tube 44, eventually the current through theneon tube 44 will fall below the level necessary for maintainingconduction in the neon tube 44 and the neon tube will extinguish,cutting o1rthe discharge path for the capacitors. With the dischargepath for the capacitors 42 and 48 cut off they again start to be chargedby the current flow through resistor 60 and thus the charging anddischarging cycle repeats itself. This alternate charging anddischarging of the capacitors 46 and 50 produces a series of pulsesacross each of resistors 42 and 48 which are summed to produce adifferen'tial output across both resistors 46 and 50 since currentthrough these resistors is in opposite directions.

The value of the capacitors 42 and 4'8 are equal as are the values ofthe resistors 46 and 50. Thus the differential output across theresistors 46 and 50 is theoretically the lowest voltage possible acrossthe two resistors with the circuit operating as described above.

When a person approaches the urinal to use it he comes between the plate36 and ground so that the capacity between the plate 36 and ground isincreased. When he is positioned to use the urinal this increase isabout 2 to 3 picofarads. This capacity is then added in series withcapacitor 40 across capacitor 42, thus changing the total capacitybetween the ground terminal 32 and resistor 60. This increases thecurrent flow through resistor 46 changing the differential voltageacross resistors 46 and 50 from the mentioned null value, making thetotal voltage across resistors 50 and 46 more positive. Because of thesize of the change in capacity, the change in voltage is not very large.However, it is detectable and to increase its magnitude an amplifyingcircuit 62 is employed.

As pointed out above, the capacitance of capacitors 42 and 48 are equaland the resistance of resistors 46 and 50 are equal. It has been foundas is described in the above mentioned copendin g application that bymaking these capacitors and resistors equal the oscillator is madeinsensitive to changes in the characteristics of the neon tube 44 or thevoltage supplied to charge the capacitors and has in addition been foundto make the oscillator extremely reliable when employed in detectingvery small changes in capacity.

With theoscillator circuit as described up till now itwould be assumedthat null voltage of the differential output across resistors 46 and 50is quite small because capacitor 42 equals capacitor 48 and resistor 46equals resistor 50. However, because the size of the change in magnitudeof the differential output across resistors 46 and 50 caused by a personstanding in front of the urinal is itself quite small, this voltage issufficient to interfere with the detection of this change in thedifferential output. Though it is not sure what causes this relativelylarge null voltage, it is assumed that it is due to the fact thatresistors 46 and 50 are in the charging path of capacitor 48 While thereis no comparative resistance I in the charging path of capacitor 42.However, no matter what the cause of this null voltage is, it has beenfound that employing a large resistor 64- and a blocking capacitor 66 inshunt with capacitor 48 materially reduces the null voltage so it is nolonger a factor in detection of the changes in the magnitude of thedifferential output across resistors 46 and 50 due to the body capacityof an individual using the urinal. The differential output acrossresistors 46 and 50 is fed into the input of the above-mentionedamplifier 62.

The amplifier 62 has two stages. The first stage of the amplifiercomprises a first transistor 68 with its base to emitter path connectedacross resistors 4-6 and 50 in series with resistor 70, with a resistor72 coupling its collector to the output of the D.C. power supply 52, andwith a resistor 74 connecting its base to its collector for biasingpurposes.

The current amplified differential output of the first stage of theamplifier 62 is fed into the second stage of the amplifier through acapacitor 7 6, coupling the emitter of the first transistor 68 to thebase of a second transistor 78. The emitter of the second transistor 78is connected to ground while the collector of the second transistor 78is connected to the collector of the first transistor 68 throughresistor 80. A resistor 82 and capacitor 84 are connected in shuntbetween the collector of the first transistor and the ground terminal 32for biasingand filtering purposes respectively, and a resistor 86 isconnected between the base and the emitter of the second transistor 78to bias the base with respect to the emitter. Like the V firsttransistor 68, the second transistor 78 has a resistor 88 connecting itsbase to its collector for biasing purposes.

The output of the second stage ofthe amplifier 62 or the collector ofthe second transistor 78 is connected by,

a capacitor 92 to the base of a germanium four layer PNPN semiconductorswitching device 90, such as a 2Nl966. Connected in series between theemitter and collector of this semiconductor switching device is a diode96 and the coil 94 of a relay 95. In shunt with the coil 94 is acapacitor 98 and in shunt across the emitter and collector is a diode100.

The emitter to. collector path of the semiconductor switching device 90is connected in series with a capacitor 102 and a resistor 104 acrossthe excitation terminals 22 and 32 so as to couple the AC source to thesemiconductor switching device. However, only negative current can flowthrough the semiconductor switching device from the AC. source becausepositive current is shunted past the semiconductor switching device bythe diode 100. Whether negative current actually will flow through thesemiconductor switching device 90 will depend on the tor 108 and a diode110 connected between the base of the semiconductor switching device 90and the AC. excitation terminal 22. This bias circuit supplies apositive potential to the base while the collector is negative, andWhile no one is in the area of use of the urinal the pulses supplied bythe oscillator through capacitor 92 are not sufiicient to drive the basenegative while the collector is negative. Therefore, while the urinal 10is not used, the semiconductor switching device 90 remains nonconductiveduring the negative half cycles of excitation applied thereacross. flowthrough the capacitor 102, the resistor 104 and past the semiconductorswitching device through the diode 96 and the coil 94 during thenegative half cycles. This current flow through the coil 94 issufficient to energize the relay 95. Though positive current is shuntedto ground by the diode 100, diode 96 isolates the coil 94 from the pathto ground through the diode 100 during this time to preventdeenergization of the relay 95, so that the relay is energized all thetime the semiconductor switching device 90 is nonconductive.

- With the relay energized the armature 112 of the relay is in contactwith contact 114. The armature of This means that current will 120 andthe coil 33 which are connected in series between the contact 114 andthe grounded terminal 32. Initially there is no charge on the capacitor118 so that the fact that the capacitor 118 is connected across the coil33 does not mean that the relay 28 will be energized.

When someone approaches the urinal to use it'his body changes thecapacity between the plate 36 and ground. As pointed out previously thisprovides a change of the output between the resistors 46 and 50 toprovide pulses greater in magnitude than the mentioned null potential.These pulses of increased amplifier 62 and fed to the base of thesemiconductor switching device 90 in the form of negative pulses whichdrive the base of the semiconductor switching device 90 sufiicientlynegative during the negative half cycles vto cause it to conduct. Whenthe semiconductor switching device 90 conducts, all excitation for thecoil 94 is shunted past the coil 94, during positive half cycles bydiode 100 and during negative cycles by the semiconductor switchingdevice. Therefore, the relay 95 becomes deenergized. With the relay 95deenergized, the armature 112 moves away from the contact 114 andcontacts contact 120. This puts the capacitor 118 in series with a diode122 and v a resistor 124 across the 115 v. 60 cycle line so that thecapacitor 118 starts charging. So long as the semiconductor switchingdevice is conductive, the armature 112 remains against the contact 120and the capacitor charges towards 115 v. However, the charge on thecapacitor is limited by a resistor 128 and a neon tube 130 connectedbetween the contact 120 and ground. The neon tube 130 breaks down andconducts when the voltage across the capacitor reaches the breakdownpotential of the neon tube. The capacitor 118 then remains at thispotential until the relay is reenergized.

The relay is reenergized when the person using the urinal leaves thevicinity of the urinal. This reduces the capacitance between the metalplate 36 and ground and therefore restores the dilferential outputacross the resistors 46 and 50 to null. As pointed out previously, withthe output across resistors 46 and 50 at its null value thesemiconductor switching device is deenergized, thus allowing current toflow through the coil 94 so that the relay 95 again becomes energized.With the relay 95 energized the armature 112 is against contact 114 sothat the capacitor 118 is again connected across coil 28. This time,however, the capacitor 118 is charged and current flows through resistor120 and the coil 33'enengizing the first mentioned relay. This attractsthe armature 26 to the contact 30 coupling the flush valve actuatingmeans 16 across the 115 v. 60 cycle excitation which of course, asmentioned above, causes the valve actuating means to flush the urinal.The relay remains energized until the charge on the capacitor 118 isdissipated and then the relay 28 becomes deenergized removing thearmature 26 from the contact 30 to cut off the excitation to the valveactuating means 16. Thus it can be seen that the length of the flushingdepends on the charge on capacitor 118 which in turn depends on thebreakdown potential of the neon tube 130 and the value of resistor 128.The resistor 128 and neon tube 130 are selected so as to give asufficient flush to clean the urinal, but at the same time are selectedto prevent the flushing from being excessive and thus wasting of waterand delaying the time when the next person can use the urinal.

It will be noticed that it will take time to charge capacitor 118through resistor 124, the time of course depending on the respectivevalues of capacitance and resistance. This means that the semiconductorswitching device 90 must remain conducting for a certain length of timeto charge the capacitor 118 sufiiciently to energize the relay 28 whichin turn means that a person must stand in position in front of the plate36 for a given period of time before the relay 28 will be energized Thisprevents the urinal from being flushed by an occasional passerby whodoes not intend to use the urinal but merely happens to potential areamplified-by the.

switch, such as a Tung-Sol TS X 305C, inplace of the relay 28, capacitor118, diode 122, neon tube 130 and resistors 120, 124, 128. In thiscircuit the armature 112 is connected to the terminal 22 and one side ofthe valve actuating mechanism 16 is connected to the grounded terminal32. One terminal of the heater 1 32 for the thermal relay 1-34 is alsoconnected to the grounded-terminal 32 and the other terminal of theheater 132 is connected to contact 120. Contact 114 of the relay isconnected to the blade 136 of the terminal switch while the otherexcitation terminal of the valve actuating means 16 is connected to acontact 138 of the thermal switch which remains open so long as thethermal switch is cool. Therefore, the flush valve actuating mechanism 16 normally remains unenergized. However, when someone approaches theurinal and thereby causes the relay to be deenergized, the v. excitationis placed-across the heater coil 132. If a person stands in front of theurinal for a sufiicient length of time, approximately 8 seconds,

the heater coil will snap the thermal switch snap blade 136 against thenormally open contact 138. This does not energize the valve actuatingmeans 16 because the circuit is still open at contact 114 so long as therelay is deenergized. When a person standing in front of the urinalmoves away the relay again becomes-energized. This causes the armature112 to again contact contact 1'14 completing the excitation circuit forthe flush valve mechanism 16. At the same time energization of the relayopens up the circuit to the heater coil '13-2, the heater coil to cool.When the heater coil cools sulficiently the thermal switch blade willagain snap causing it to move away from contact 138 and open up theenergizing circuit for the valve actuating mechanism 16, thus ending theflushing of the urinal.

Described above is a complete embodiment of the present invention andmodification of that embodiment. It; should be obvious to those skilledin the art that certain allowing 7 changes can be made in theseembodiments without departing from the spirit and scope of theinvention. Therefore, it will be understood that this is intended tocover all modifications or changes in the disclosed embodiments which donot depart from the spirit and scope of the invention as expressed inthe claims.

What is claimed is:

1. An automatic flusher for a toilet comprising:

(a) capacity sensitive means for detecting body capacity in the area ofuse of the toilet;

(b) actuating means for flushing the toilet;

(c) means responsive to said body capacity for operating the actuatingmeans for flushing the toilet after the capacity sensitive means detectsa minimum level of body capacity for at least a predetermined length oftime and thereafter detects an absence of such a level of body capacity;and

((1) means for delaying the flushing of the toilet for a period aftersaid capacity sensitive means detects said absence of body capacity.

2. An automatic flusher for a toilet comprising:

(a) capacity sensitive means for detecting the presence of a person inthe area of use of a toilet and for providing signals indicative of thepresence or absence of such a person;

(b) actuating means for flushing the toilet; and

(0) electric circuit means including a low frequency oscillator fordetecting such signals to determine if the length of time of suchpresence exceeds or falls below a predetermined minimum length of timeand for causing said actuating means to flush the toilet only when thelength of time of such presence exceeds the predetermined minimum andsaid presence is no longer detected.

3. Anautomatic flusher for a toilet comprising:

(a) a capacity sensitive plate for detecting the body capacity of aperson positioned to use the toilet;

(b) a low frequency oscillator means responsive to change in capacitydetected by said capacity sensitive plate resulting from persons'approaohing and leaving the toilet for providing signals indicative ofsaid changes;

(c) actuating means for flushing the toilet; and

(d) means responsive to said signals for operating the actuating meansto flush the toilet when the capacity sensitive plate detects the bodycapacity of a person in the area of use of the toilet and thereafterdetects his absence from the area of use of the toilet,

said :last mentioned means being operative only after the body capacityof, a person in the area of use has been detected at least for apredetermined time.

References Cited by the Examiner UNITED LAVERNE D. GEIGER, PrimaryExaminer.

H. ARTIS, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,3l4,08l April 18 1967 Carl E. Atkins et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 1, line 43, for "system read systems column 3, line 21, for "46and 50" read 42 and 48 line 22, for "42 and 48" read 46 and 50 column 4,line 47, for "58" read 38 column 6, line 13, for "terminal" read thermalcolumn 8 line 4 for "Bikser" read Bokser Signed and sealed this 14th dayof November 1967.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer

1. AN AUTOMATIC FLUSHER FOR A TOILET COMPRISING: (A) CAPACITY SENSITIVEMEANS FOR DETECTING BODY CAPACITY IN THE AREA OF USE OF THE TOILET; (B)ACTUATING MEANS FOR FLUSHING THE TOILET; (C) MEANS RESPONSIVE TO SAIDBODY CAPACITY FOR OPERATING THE ACTUATING MEANS FOR FLUSHING THE TOILETAFTER THE CAPACITY SENSITIVE MEANS DETECTS A MINIMUM LEVEL OF BODYCAPACITY FOR AT LEAST A PREDETERMINED LENGTH OF TIME AND THEREAFTERDETECTS AN ABSENCE OF SUCH A LEVEL OF BODY CAPACITY; AND (D) MEANS FORDELAYING THE FLUSHING OF THE TOILET FOR A PERIOD AFTER SAID CAPACITYSENSITIVE MEANS DETECTS SAID ABSENCE OF BODY CAPACITY.